When the activity had finished 1 hours later, a head count was taken and 10 students were identified as missing.
The three adults, all women, immediately carried out a search.
But they did not notify camp administrator Gerry Hart, who was off-site, for another 2 hours, at 3pm. Mr Hart notified Tauranga Intermediate School principal Brian Diver at 3.36pm and, two minutes later, dialled 111.
At 4pm, senior school staff and police arrived at the camp and a major search and rescue operation started.
At 7.50pm, the missing students were found.
The students, all girls, had mistakenly taken a side track, known as the Main Leyland O'Brien Track, 120m from where they had entered the bush. They were not found until eight hours later - 10km from their original location.
Mr Diver told the Bay of Plenty Times Weekend the incident was regrettable, and despite the fact thousands of students had completed the 390m loop track in the camp's history, on this occasion four main things went wrong:
The briefing students were given by teachers was "inadequate".
Teachers in charge did not give early notification of missing students.
Some pupils did not follow instructions.
The three adult supervisors did not have adequate visibility of the pupils. The loop track, which generally takes six minutes to walk around, saw one teacher stationed on a bridge 280m from the lodge, one teacher where pupils exit the loop track and one teacher at the top of the loop track.
Mr Diver said the day before the exercise, camp administrator Gerry Hart had taken all 51 students up the Main Leyland O'Brien Track.
"To this day, we can't fathom why they kept walking uphill away from the camp," Mr Diver said.
"In the 18 years that I've been principal of the school, not one kid has been lost (up until this incident)."
Mr Diver, who is a Ngamuwahine Lodge trustee, said trustees had apologised on behalf of the school for the distress and trauma caused to all involved.
The inquiry report, which has been put together by trustees in consultation with Search and Rescue, police, Department of Conservation, Tauranga Hospital emergency team and the 10 lost students, stated: "Some students went missing because they did not listen and because they did not understand some aspects of the briefing.
"Improved supervision and briefing by staff would have lessened the probability of some students wandering off the loop track."
The report went on to state that the first response team to any emergency could not be activated because notification came too late.
Mr Diver said the teachers accepted their mistakes and had apologised.
The two teachers, both of whom had been at the school for three and five years respectively, would be allowed back to the camp, Mr Diver said.
"We are absolutely certain and trust that they will never repeat the inadequate briefing they did this year. The community can rest assured that the whole staff at Tauranga Intermediate, who are all involved in mandatory camp activities at Ngamuwahine, have been briefed and will continue to be briefed on their responsibility for the safety of students," Mr Diver said.
"This has given us a bloody good fright and we were lucky to get away with a non-injury incident."
All 10 children lost in the bush were offered counselling and some had accepted. Mr Diver said the large majority of school parents and the community had been supportive.
He believed the reputation of the school and camp had been enhanced because of the "transparency and thoroughness" of the investigation.
Ministry of Education acting regional manager regional education and performance Chris Day said the incident had been dealt with in an "effective manner".
